GameSparks is a good mobile backend as a service option, and one of the more popular ones. It is flexible and has a good set of features. It runs a MAU (Monthly Active Users) cost which can be confusing, leading people to think it’s too expensive when, in fact, it offers quite a competitive price.

A young player in the game, PlayFab has only been around a bit over a year (it was in development for three years under the name Uber Entertainment) – it launched in September 2014. Some will say it is the most complete backend platform, especially after it partnered with Photon, the multiplayer cloud service. Some of the features include player accounts, virtual goods management, in-game messaging, and game data storage.

The key selling point of HeroicLabs is the API which allows game developers to easily integrate multiplayer and social elements without needing a server backend. It focuses and optimizes mostly for massive games, games of high volume. HeroicLabs also has a code sample with SOOMLA in our knowledge base.

Gamedonia is another complete backend solution for mobile games. The cloud platform for game developers does not require a server and offers many social games and real-time elements such as PvP (player versus player) modules, in-game chat or social sharing. Gamedonia was founded in 2012 and besides offering mobile support, also works in the browser.

Kii is another developer sweetheart and a Unity partner, making its community support quite strong. Its key selling point is a burst limit of 150 API calls per second, which is quite important. On the other hand, it does not allow anonymous users. Other features include server extensions, push notifications, leaderboards and achievements. It supports iOS, Android and Windows 8.

Kinvey is one of the pioneers in the MBaaS game, which by default makes it a strong contestant for the best service out there. Compared to Parse, I’d say the two are quite similar in features: it offers cloud storage and push notifications. There’s also an easy way to integrate Facebook Open Graph for all those apps without websites. However, like Parse, it’s a general purpose MBaaS for all mobile apps, not just games.

brainCloud might make your brain hurt of all the features it offers. It calls itself “backend in a box.” It is a ready-made, cloud-based backend designed for game developers, allowing them to jumpstart their game creation with various pre-built features. Its features include Cloud Data, including user and global statistics, shared data and custom files, Multiplayer, with support for turn-by-turn and one-way offline (clash-style) multiplayer. Other features include Achievements, Leaderboards and Monetization features.

Flox is a scalable and lightweight cloud backend for mobile games built by Gamua. It runs on all mobile devices supported by Adobe AIR, and also allows offline play. Players can be authenticated through Google+, Facebook, email or the iOS GameCenter API. It comes with rich documentation and a powerful customer support. If you’re developing with AIR, or specifically the Starling framework, this is the backend for you.

App42 is another popular solution. It has many features, including all the usual ones like leaderboards, cloud storage or social sharing. It used to be cheaper than Parse (now it definitely is), while offering the same burst limit. A great solution for any mobile game developer.

Photon is a cross-platform multiplayer game backend – a service tailored especially for game developers. It allows you to easily add multiplayer to your games and run them in the Global Photon Cloud. You can also host your own Photon servers, if that kind of hybrid is your thing. It is a good choice for game developers of all sizes, from indies to AAA studios.

Great list! We use Playfab for our upcoming game Clicker Pirates and Flox for Takos Japanese they both work great, and they are very easy to set up and use.
You should also mention that Playfab is now free to use ;)